Dunja Šamec

Biflavonoids are dimeric flavonoids recognized for their diverse biological activities and significant pharmacological potential, with ginkgo (Ginkgo biloba L.) serving as a primary natural source. This study presents a comprehensive spatiotemporal characterization of the biflavonoid profile across a diverse population of 90 trees. High-resolution chromatographic analysis quantified five major biflavonoids, revealing a consistent hierarchical abundance: sciadopitysin > isoginkgetin > ginkgetin > bilobetin > amentoflavone. Notably, sciadopitysin emerged as the predominant constituent (1532.89 ± 544.13 µg/g dw). To decode the complex drivers of metabolite accumulation, we integrated Principal Component Analysis (PCA) with Piecewise Linear Regression (PLR). PCA confirmed a robust chemical structure, explaining 71.5% of the total variance, where Factor 1 represents a general biflavonoid gradient and Factor 2 captures localized environmental influences. The PLR models (R² = 0.75–0.83) identified tree age as a primary negative regulator, showing a significant decline in total biflavonoids as trees mature beyond the 30-year reproductive threshold. While sexual dimorphism and location exhibited compound-specific nonlinear effects, younger trees (10–30 years) demonstrated the highest biosynthetic plasticity and potency. These findings establish a predictive framework for optimizing the pharmaceutical harvest of ginkgo leaves, highlighting that age-related physiological shifts, rather than gender or broad geography, are the critical determinants of biflavonoids yield.

The growth of the global population has led to increased demand for agricultural products, resulting in greater agricultural waste production. One sustainable response to this challenge is using agricultural waste as raw material in building materials. This study examines the potential for partial replacement of natural aggregates in concrete with agricultural waste from typical Mediterranean fruits: sour cherry pits, grape seeds, ground olive pits, and carob seeds. To evaluate the effect of treatment on the behavior of agro-waste aggregates, ground olive pits were used untreated, treated with ash water, or treated with seawater. Carob seed concrete deteriorated during water curing due to seed swelling and tannin-related degradation, revealing its unsuitability without prior stabilization. Partial replacement of natural aggregates with agricultural waste resulted in decreased density, ultrasonic pulse velocity (UPV), dynamic elastic modulus, compressive strength, and thermal conductivity, while increasing saturated water absorption. Treatment with ash water on ground olive pits improved the interfacial transition zone (ITZ), resulting in 29% increase in compressive strength relative to untreated ground olive pits. Concrete with ash water treated ground olive pits demonstrated the highest practical potential among all tested agro-waste concretes.

Oxidative aging drives asphalt pavement degradation, causing critical structural failures. This study evaluated hazelnut (HS) and walnut shell (WS) powders (0–3% w/w; 10–12 μm) as sustainable antioxidants, from valued residues, to mitigate thermo-oxidative aging in CA-24 binders. After evaluating the antioxidant potential (ORAC; Oxygen radical absorbance capacity, and TPC; Total phenolic content), modified binders underwent RTFO (Rolling thin film oven) and PAV (Pressure aging vessel) aging, evaluated by Fraass fragility, Relative Aging Index (RAI), dynamic shear rheometry (G*/sin δ), and Multiple Stress Creep Recovery (MSCR). WS exhibited significantly higher antioxidant capacity (6000 μmol TE g DW⁻¹) and TPC than HS. The 3% treatments demonstrated optimal antioxidant efficacy, reducing long-term RAI by 14% and improving low-temperature flexibility by 3.8 °C (Fraass point −12.3 °C). However, MSCR revealed initial plasticizing effects decreasing elastic recovery (70%) and increasing non-recoverable compliance (Jnr) compromising unaged rutting resistance. Principal component analysis confirmed progressive diversification of aging-induced properties, evidencing complex multivariate trajectories. Ultimately, while nutshell derived phenolic modifiers provide effective concentration-dependent antioxidant protection, practical application requires optimization through targeted phenolic extraction, particle engineering, or elastomeric co-modification. Balancing aging resistance with high temperature stability remains essential for advancing these sustainable biomodification strategies in road infrastructure.

This study investigates the effects of agro-waste-based capsules made from grape seeds and cherry pits on the physical, mechanical, thermal and self-healing properties of concrete. Capsule-containing mixtures were compared with a reference concrete after 28 days of water curing using both standardized and non-standardized testing methods. Capsule incorporation reduced workability by up to 91% and altered air content depending on capsule type, increasing it by 47% for grape seed capsules and decreasing it by 65% for cherry pit capsules. Fresh concrete density was reduced by 5.5% and 6.8% for grape seed and cherry pit capsules, respectively, while hardened concrete density decreased by 11% and 9%, implying lighter structures with improved seismic resistance. Compressive strength decreased by 49% for grape seed capsules and 27% for cherry pit capsules. Thermal conductivity was reduced by 32% and 22%, respectively, indicating improved energy efficiency. Concrete with grape seed capsules showed freeze–thaw performance comparable to the reference concrete after 112 cycles, whereas concrete with cherry pit capsules exhibited superior dynamic modulus behavior, suggesting continuous crack healing, despite significant mass loss due to poor capsule–matrix bonding. SEM analysis showed no significant crack reduction, while EDS revealed calcium-rich areas in grape seed capsule concrete, indicating possible crack healing. Overall, agro-waste capsule concrete shows potential for improving seismic resistance and energy efficiency, although further research is required to clarify the self-healing effect.

Biflavonoids, or flavonoid dimers, are characteristic phytochemicals of ginkgo associated with various biological activities, yet they remain far less studied than monomeric flavonoids. For their effective industrial application, optimization of extraction conditions is essential. This study investigated the effect of ethanol–water ratio (0, 10, 30, 50, 70, and 96% ethanol) on the extraction efficiency of major ginkgo biflavonoids (amentoflavone, bilobetin, ginkgetin, isoginkgetin, and sciadopitysin). Three ginkgo tissue types, green leaves, yellow leaves, and sarcotesta, previously reported to accumulate biflavonoids, were analyzed. Biflavonoids were quantified by HPLC-DAD, and total polyphenol content and antioxidant activity were also determined. Biflavonoids were most abundant in yellow leaves, with sciadopitysin identified as the dominant compound. No biflavonoids were detected in water or 10% ethanol extracts, while 30% ethanol extracts contained detectable biflavonoids only in yellow leaves at low concentrations. For most biflavonoids, the highest concentrations were obtained using 70% and 96% ethanol. Considering comparable extraction efficiency and lower toxicity, 70% ethanol was identified as the most suitable solvent. These findings highlight the importance of tissue type and solvent composition for efficient biflavonoid extraction from ginkgo.

Salinity is one of the major abiotic stresses limiting chickpea (Cicer arietinum L.) productivity, particularly in arid and semi-arid regions where soil salinization is intensifying. Developing cost-effective and practical strategies to enhance seedling establishment and early vigor under saline conditions is therefore essential. In this study, we compared two seed-priming agents—1 mM proline and 25 mM NaCl—under identical hydroponic conditions to elucidate tissue-specific responses to 25 mM NaCl stress. Proline priming significantly improved shoot length (by ~23%), total chlorophyll content (by ~19%), and ascorbate peroxidase (ASPOX) activity. In contrast, NaCl priming enhanced root biomass retention (by ~38%) and peroxidase (POD) activity under salinity stress. Both priming treatments induced higher proline accumulation and antioxidant capacity, though with tissue-specific effects: proline favored aboveground resilience, while NaCl strengthened root ionic and oxidative balance. These findings highlight the complementary nature of proline and NaCl priming and support the concept of stress “memory,” whereby plants acquire enhanced readiness to cope with salinity. Integrating such priming strategies into chickpea cultivation could contribute to improved yield stability and sustainability in saline agroecosystems.

Climate change poses a serious threat to global agriculture, biodiversity, and food security, underscoring the need to develop crops with enhanced resilience to abiotic stresses. Methodological advancements in transcriptomics and metabolomics have revolutionized the assessment of crop stress resilience, providing comprehensive and high‐resolution insights into plant responses at the molecular and biochemical levels. Transcriptomics enables detailed profiling of gene expression patterns and regulatory networks activated under stress conditions, whereas metabolomics offers comprehensive profiling of metabolites involved in stress adaptation, signaling, and cellular homeostasis. Recent innovations in high‐throughput sequencing, long‐read transcriptomics, and advanced mass spectrometry techniques have expanded analytical sensitivity, specificity, and throughput. This review critically examines the latest methodological developments in transcriptomics and metabolomics, emphasizing their synergistic potential in decoding plant stress resilience. In addition, we discuss key challenges in cross‐omics data integration, including computational complexity, standardization, and environmental variability, and highlight emerging solutions such as spatial omics, AI‐assisted analytics, and high‐throughput phenotyping. By utilizing these cutting‐edge methodologies, researchers can enhance predictive modeling, accelerate stress‐resilient crop breeding programs, and contribute to the development of climate‐smart agriculture, ultimately supporting global food security. With advanced technologies, researchers can better understand complex regulatory networks, identify resilience‐associated biomarkers, and accelerate the development of climate‐resilient crops. Climate‐resilient crops can be developed by understanding complex regulatory networks and identifying resilience‐associated biomarkers. Ultimately, integrative omics approaches will play a crucial role in supporting sustainable agriculture and global food security. Integrating transcriptomics and metabolomics with AI‐based analytics offers new precision tools for evaluating crop stress.

Biflavonoids, a unique class of naturally occurring polyphenolic compounds formed by the dimerization of flavonoid units, have attracted increasing scientific interest due to their diverse biological activities and structural complexity. This review provides a comprehensive overview of their natural occurrence, synthetic strategies, and antimicrobial properties, with a particular focus on their antibacterial, antifungal, and antiviral activities. Comparative analyses indicate that biflavonoids often display enhanced or distinct biological effects compared to their monomeric flavonoid counterparts, suggesting that dimerization plays a crucial role in modulating bioactivity. Overall, biflavonoids represent an underexplored yet highly promising group of natural compounds with significant potential for the development of novel antimicrobial and antiviral agents. Continued interdisciplinary research integrating natural product chemistry, pharmacology, and computational modeling will be essential to fully realize their therapeutic potential.

Ginko (Ginkgo biloba L.) is a widely distributed ornamental tree that produces large quantities of leaves annually, turning golden yellow in autumn due to chlorophyll degradation and carotenoid retention. While green ginkgo leaves and standardized extracts have been extensively studied, senescent and naturally fallen leaves remain only scarcely investigated, despite representing a substantial biomass resource. In this study, we analyzed yellow ginkgo leaves collected directly from trees and those naturally shed at four time points during autumn. We determined pigment composition, total polyphenols, flavonoids, phenolic acids, and the concentrations of five major biflavonoids. Chlorophylls decreased progressively in tree-collected leaves, whereas carotenoid levels remained stable or slightly elevated. Polyphenolic compounds were more abundant in fallen leaves. Biflavonoid profiling revealed the presence of amentoflavone, bilobetin, ginkgetin, isoginkgetin, and sciadopitysin, with sciadopitysin as the most abundant. Total biflavonoid content reached up to 8 mg/g dw, with higher levels in fallen leaves compared to those collected from the tree. These findings highlight yellow ginkgo leaves, particularly fallen ones, as a sustainable and non-invasive source of pharmacologically relevant biflavonoids. However, further research is needed to optimize eco-friendly extraction strategies and to evaluate safety aspects.

Biflavonoids are an important group of flavonoids found in Juniperus species, yet their distribution and accumulation patterns remain insufficiently explored. In this study, we applied a method for the simultaneous quantification of seven biflavonoids to analyze different plant parts of J. communis, J. communis subsp. nana, and J. oxycedrus. In order to determinate the influence of growing location, we also analyzed J. communis samples collected from different locations. Four biflavonoids—cupressuflavone, amentoflavone, bilobetin, and hinokiflavone—were detected. In both analyzed J. communis varieties, amentoflavone was the predominant biflavonoid in cones and needles, while in J. oxycedrus, cupressuflavone was the most abundant in cones, with amentoflavone dominating in needles. Overall, biflavonoid content was significantly higher in needles than in cones, with total biflavonoid levels in needles exceeding 5 mg/g dw, highlighting the tissue-specific nature of biflavonoid biosynthesis within Juniperus species. Additionally, our results suggest that in J. communis, biflavonoid accumulation is significantly influenced by growing location.